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BFNA Title: Donnellia |
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XX. DONNELLIA Austin, Bull. Torrey
Bot. Club 7: 15. 1880 * [for John
Donnell Smith, 1829--1928] William R. Buck Meiotheciopsis Brotherus Leaves erect to erect-spreading, sometimes
homomallous when dry, oblong-lanceolate to lanceolate-ovate, gradually short-acuminate,
concave; distal cells long-rhomboidal to long-hexagonal, smooth; alar cells
enlarged, thick-walled, colored in 1--3 rows, scarcely inflated. Sexual
condition autoicous. Seta
short, smooth. Capsule erect to
suberect, small, short-cylindric, slightly or not contracted below the mouth;
exothecial cells somewhat collenchymatous; annulus none; peristome double,
pale, exostome teeth on exterior surface with straight center line, not
furrowed, smooth (not cross-striolate), scarcely projecting at back;
endostome with very low or absent basal membrane, segments linear, ± keeled, not perforate, finely papillose, almost as long
as the teeth, sometimes fugaceous, cilia none. Spores large. Species 5 (1 in the flora): most common in tropical
America, but also extending into tropical Africa; North America, Central America, n South America, c Africa. SELECTED REFERENCES Buck, W. R. 1988. Donnellia
(Sematophyllaceae) resurrected and refound in Florida after 110 years. Bryologist 91: 134--135. Buck, W. R. 1994. A synopsis of the
American species of Donnellia (Sematophyllaceae). Hikobia 11: 377--385. 1. Donnellia commutata (J.
F. K. Müller) W. R. Buck, Bryologist 91: 134. 1988 Neckera
commutata
J. F. K. Müller, Bot. Zeit. 15: 385. 1857; Donnellia floridana Austin, illegitimate name; Fabronia donnellii
Austin; Meiotheciopsis commutata
(J. F. K. Müller) W. R. Buck; Meiothecium
tenerum Mitten Stems irregularly branched, the branches ascending. Leaves
homomallous, lanceolate, 0.6--1.1 ´ 0.19--0.36 mm, only slightly
concave; margins entire; cells thick-walled and long-rhomboidal throughout;
alar cells shortly oblong, thick-walled, yellow, slightly inflated, in a
single row, those directly above not inflated or colored, quadrate. Seta
2.5--3.5 mm. Capsule 0.7--1.2 mm;
peristome bone white when dry, ±
translucent when moist, exostome teeth with conspicuous lamellae on front
surface; endostome fragile, appearing lacking in deoperculate capsules. Capsules mature winter.
White-sand evergreen oak scrub forests, mostly growing on trunks and
large branches (including those in the canopy) of Quercus spp.; low elevations; nc Fla.; Mexico to southern
Brazil; Greater Antilles. This species is not uncommon in oak scrubs of
north-central Florida, but has been mostly overlooked because of its sympatry
with and morphological similarity to Sematophyllum
adnatum, one of the great weedy mosses. Donnellia commutata
may be distinguished satisfactorily only when fertile by its shorter setae,
white peristome (when dry), and ±
smooth exostome teeth. The endostome
often appears absent because the segments break off shortly after the loss of
the opercula. However, they can be
easily demonstrated by the dissection of mature, operculate capsules. |